Contract Source Code:
File 1 of 1 : Groovy
// SPDX-License-Identifier: No License
pragma solidity 0.6.12;
// ----------------------------------------------------------------------------
// 'Groovy.finance' token contract
//
// Symbol : Gvy
// Name : Groovy.finance
// Total supply: 42 000
// Decimals : 18
// ----------------------------------------------------------------------------
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath{
function mul(uint256 a, uint256 b) internal pure returns (uint256)
{
if (a == 0) {
return 0;}
uint256 c = a * b;
assert(c / a == b);
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256)
{
uint256 c = a / b;
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256)
{
assert(b <= a);
return a - b;
}
function add(uint256 a, uint256 b) internal pure returns (uint256)
{
uint256 c = a + b;
assert(c >= a);
return c;
}
}
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/
contract Ownable {
address public owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/
constructor () internal {
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(msg.sender == owner);
_;
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/
function transferOwnership(address newOwner) onlyOwner public {
require(newOwner != address(0));
emit OwnershipTransferred(owner, newOwner);
owner = newOwner;
}
}
/**
* @title ERC20Basic
* @dev Simpler version of ERC20 interface
* @dev see https://github.com/ethereum/EIPs/issues/179
*/
interface ERC20Basic {
function balanceOf(address who) external view returns (uint256 balance);
function transfer(address to, uint256 value) external returns (bool trans1);
function allowance(address owner, address spender) external view returns (uint256 remaining);
function transferFrom(address from, address to, uint256 value) external returns (bool trans);
function approve(address spender, uint256 value) external returns (bool hello);
event Approval(address indexed owner, address indexed spender, uint256 value);
event Transfer(address indexed from, address indexed to, uint256 value);
}
/**
* @title Basic token
* @dev Basic version of StandardToken, with no allowances.
*/
/**
* @title Standard ERC20 token
*
* @dev Implementation of the basic standard token.
* @dev https://github.com/ethereum/EIPs/issues/20
* @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
*/
contract StandardToken is ERC20Basic, Ownable {
uint256 public totalSupply;
using SafeMath for uint256;
mapping(address => uint256) balances;
/**
* @dev transfer token for a specified address
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
*/
function transfer(address _to, uint256 _value) public override returns (bool trans1) {
require(_to != address(0));
//require(canTransfer(msg.sender));
// SafeMath.sub will throw if there is not enough balance.
balances[msg.sender] = balances[msg.sender].sub(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(msg.sender, _to, _value);
return true;
}
/**
* @dev Gets the balance of the specified address.
* @param _owner The address to query the the balance of.
*/
function balanceOf(address _owner) public view override returns (uint256 balance) {
return balances[_owner];
}
mapping (address => mapping (address => uint256)) allowed;
/**
* @dev Transfer tokens from one address to another
* @param _from address The address which you want to send tokens from
* @param _to address The address which you want to transfer to
* @param _value uint256 the amount of tokens to be transferred
*/
function transferFrom(address _from, address _to, uint256 _value) public override returns (bool trans) {
require(_to != address(0));
// require(canTransfer(msg.sender));
uint256 _allowance = allowed[_from][msg.sender];
// Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
// require (_value <= _allowance);
balances[_from] = balances[_from].sub(_value);
balances[_to] = balances[_to].add(_value);
allowed[_from][msg.sender] = _allowance.sub(_value);
emit Transfer(_from, _to, _value);
return true;
}
/**
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
*
* Beware that changing an allowance with this method brings the risk that someone may use both the old
* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
* @param _spender The address which will spend the funds.
* @param _value The amount of tokens to be spent.
*/
function approve(address _spender, uint256 _value) public override returns (bool hello) {
allowed[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @dev Function to check the amount of tokens that an owner allowed to a spender.
* @param _owner address The address which owns the funds.
* @param _spender address The address which will spend the funds.
*/
function allowance(address _owner, address _spender) public view override returns (uint256 remaining) {
return allowed[_owner][_spender];
}
/**
* approve should be called when allowed[_spender] == 0. To increment
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
*/
function increaseApproval (address _spender, uint _addedValue) public returns (bool success) {
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
function decreaseApproval (address _spender, uint _subtractedValue) public returns (bool success) {
uint oldValue = allowed[msg.sender][_spender];
if (_subtractedValue > oldValue) {
allowed[msg.sender][_spender] = 0;
} else {
allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
}
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
}
/**
* @title Burnable Token
* @dev Token that can be irreversibly burned (destroyed).
*/
contract BurnableToken is StandardToken {
event Burn(address indexed burner, uint256 value);
/**
* @dev Burns a specific amount of tokens.
* @param _value The amount of token to be burned.
*/
function burn(uint256 _value) public {
require(_value > 0);
require(_value <= balances[msg.sender]);
// no need to require value <= totalSupply, since that would imply the
// sender's balance is greater than the totalSupply, which *should* be an assertion failure
address burner = msg.sender;
balances[burner] = balances[burner].sub(_value);
totalSupply = totalSupply.sub(_value);
emit Burn(burner, _value);
emit Transfer(burner, address(0), _value);
}
}
contract Groovy is BurnableToken {
string public constant name = "Groovy.finance";
string public constant symbol = "Gvy";
uint public constant decimals = 18;
// there is no problem in using * here instead of .mul()
uint256 public constant initialSupply = 42000 * (10 ** uint256(decimals));
// Constructors
constructor () public{
totalSupply = initialSupply;
balances[msg.sender] = initialSupply; // Send all tokens to owner
//allowedAddresses[owner] = true;
}
}